Recommend a pair of headphones for me

I have a pair of Sennheiser HD 4.50BTNC wireless headphones (with an optional wire). I love the noise cancellation and the sound reproduction. The earpads were fantastically uncomfortable; I replaced them with some soft, kind of fuzzy ones (described as "Velvet") and I can now wear them for hours.

^ i see that one can get the Sennheiser HD 350BT for about $40 cheaper than the these. are they comparable?

at this point i'm waffling between a pair of $40 soundcore BT noise-canceling headphones (essentially the cheapest option?) and a pair of Sennheisers in the $90 - 120 range.

do I need a headphone amp if I’m already going through a stereo receiver? I’m not having volume issues at all. Do they make music sound better? Warm tubey goodness?

I've gone done that road (without spending all that much) and I would say no. Not unless your receiver sounds obviously noisy or is under-powered (like you're almost maxing it out to listen at a comfortable level).

Light dabbling in tubes I also found kind of a waste of time. And reading accounts of people with higher end stuff (who could be honest about it) it's really kinda like, well the lights look nice. Sort of like digital vs vinyl.

I have a tubey headphone amp, but I needed something as my amp didn't have a headphone jack.

The headphones I have are Beyer Dynamic DT 990's, which I mainly bought because the guy in front of me at the hifi place looked like Jimmy Page, and he bought a pair of them. He wasn't Jimmy Page, but just the fact that he looked like him made me think that there must be something to the product. They're really comfy to wear.

xxp that makes sense, kind of what I suspected. Thanks!